That was a weapon that formed its blade out of energy just like the ones he saw during recess.

Shinichi figured it was probably a simpler version of it as he thought back to Falandia.

“They had weapons like these back there too, weapons that made its blade out of mana.”

Such weapons had the advantage when it came to portability and durability, but having to use mana as fuel made them unpopular in Falandia. Molding mana into a weapon might have been possible, but no one really wanted to do it. After all, wasn’t Earth the same? Hardening gasoline and shaping it into a weapon might be possible, but no one would actually bother.

If a weapon was needed, then it was better to just use mana the proper way. Of course, sometimes the mana cost was too high, but that’s another story.

In the movies of killer robots, the professor that builds the great killer machine is usually the 1st victim.
This girl learned something about those movies. Sadly she only used what she learned to not be the 1st victim, but not to prevent the problem.

Not being the first victim might be enough, because it can lead to perfecting the skill of not being its victim at all.
And that is enough for basically anyone, heck one can then make a killer robot that will get rid of the previous one!
Thus providing both survival and an occupation!